A novel approach to evaluate fracture surfaces of aged and rejuvenator-restored asphalt using cryo-SEM and image analysis techniques. (15th February 2017)

• Record Type: Journal Article
• Authors: Mokhtari, Ali; David Lee, Hosin; Williams, R. Christopher; Guymon, C. Allan; Scholte, Jon P.; Schram, Scott
• Is Part Of: Construction & building materials. Volume 133(2017)
• Page Start: 301
• Page End: 313
• Publication Date: 2017-02-15
• Subjects: Aged asphalt -- Rejuvenator -- Cryo-Scanning Electron Microscopy -- Fracture surface -- Digital image processing -- Microscopy analysis -- Fourier Transform Infrared Spectroscopy; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2016.12.075
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Low-temperature cracking potential was evaluated using Cryo-SEM and image analysis techniques. Cryo-SEM and image analysis are identified as promising techniques in monitoring the fracture surface of aged and rejuvenator-restored binders at low temperatures. Rejuvenated binder samples indicated less stiffness at lower temperatures compared to the aged binder samples as the proposed Fracture Index (FI) values confirmed. The Fourier Transform Infrared Spectroscopy (FTIR) results were consistent with results obtained from Cryo-SEM ranking method. Abstract: Low temperature cracking potential is a primary concern for asphalt mixtures with high RAP contents. To minimize the thermal cracking, various rejuvenators have been utilized in the past. In this study, Fourier Transform Infrared Spectroscopy (FTIR) was used to determine the level of oxidation of asphalt. To evaluate the low-temperature cracking potential of aged asphalt with and without rejuvenators, the fracture surface images were captured using Cryo-Scanning Electron Microscopy (Cryo-SEM). The Cryo-SEM images were then analyzed using the image processing technique. The rejuvenated asphalt specimens exhibited less fractured surface than the aged asphalt. Finally, the Fracture Index was computed to rank each asphalt sample in terms of low-temperature cracking potential. Based on the test results, it can be concluded that the use of the Cryo-SEM technology combined with the image processing technique is a promising method to visually observe the fracture surface of asphalt and compute the Fracture Index to estimate the low-temperature cracking susceptibility.